The social media network is cracking down on the prevalence of misinformation by not allowing fake news sites to show ads on its platform.

Facebook (FB) has acknowledged that fake news is more of a problem for the site than simply a public relations issue.

On Monday, Facebook updated its policy to "explicitly clarify" that fake news sites can't use the company's Audience Network tool, which allows content publishers to display advertisements on the social media site in exchange for a cut of ad revenues, according to the Wall Street Journal.Alphabet's (GOOGL) Google made a similar move, banning misleading sites from its Google AdSense service.

The Pew Research Center found recently that 44% of Americans get at least some of their news from Facebook. That's a lot of people turning toward the Menlo Park, CA-based social media giant to find out what's going on in the world.

The prevalence of inaccurate and false news that users spread on Facebook received lots of attention in this year's presidential election, however. A recent analysis by Buzzfeed of more than 1,000 posts shared on Facebook from several news sites showed that 38% of the posts on hyper-right wing sites were either partly or entirely false, as well as 19% of those on hyper-left wing pages. By contrast, 99.3% of the posts on mainstream sites that Buzzfeed analyzed were partly or entirely truthful.

But websites pumping out false content generate a higher number of Facebook shares, comments and reactions than traditional mainstream political sites. Buzzfeed found that Occupy Democrats, the hyperpartisan site with the greatest median shares per post, earned 10,931 shares per post while, CNN Politics only garnered a median of 50 shares per post.

With lots of inaccurate content swarming news feeds, the New York Timessaid recently that fake news has become "media's next challenge."